Re: [PATCH v2 0/2] improve interactive-patch

["Rubén Justo" <rjusto@gmail.com>]

On Tue, Mar 26, 2024 at 12:13:46PM -0700, Junio C Hamano wrote:

> > On Tue, Mar 26, 2024 at 08:31:41AM -0700, Junio C Hamano wrote:
> >
> >> 'r'edisplay may work well (and I wonder "r | less" or
> >> piping the hunk display to anything in general would be a useful
> >> future enhancement).
> >
> 
> It would be more like tweaking fputs() of a strbuf that
> was filled by render_hunk() to instead spawn a pager and feed the
> same strbuf to it, or something.  IOW, we already have the payload
> to show.  We just want a pager involved in its showing so that users
> with a huge hunk that does not fit on a page can use "less" on it.

I do not plan to address this in this series, but while the topic is
warm;  Perhaps?:

--- >8 ---
diff --git a/add-patch.c b/add-patch.c
index 778f168298..cb74fe84f5 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -5,6 +5,7 @@
 #include "environment.h"
 #include "gettext.h"
 #include "object-name.h"
+#include "pager.h"
 #include "read-cache-ll.h"
 #include "repository.h"
 #include "strbuf.h"
@@ -1450,7 +1451,7 @@ static int patch_update_file(struct add_p_state *s,
 		if (file_diff->hunk_nr) {
 			if (rendered_hunk_index != hunk_index) {
 				render_hunk(s, hunk, 0, colored, &s->buf);
-				fputs(s->buf.buf, stdout);
+				fputs_to_pager(s->buf.buf);
 				rendered_hunk_index = hunk_index;
 			}
 
diff --git a/pager.c b/pager.c
index b8822a9381..f00fc87a67 100644
--- a/pager.c
+++ b/pager.c
@@ -264,3 +264,30 @@ int check_pager_config(const char *cmd)
 		pager_program = data.value;
 	return data.want;
 }
+
+void fputs_to_pager(const char* s)
+{
+	struct child_process process;
+	FILE* pager_stdin;
+	const char *pager = git_pager(isatty(1));
+
+	if (!pager) {
+		fputs(s, stdout);
+		return;
+	}
+
+	child_process_init(&process);
+
+	prepare_pager_args(&pager_process, pager);
+	pager_process.in = -1;
+	strvec_push(&pager_process.env, "GIT_PAGER_IN_USE");
+	if (start_command(&pager_process))
+		return;
+
+	pager_stdin = fdopen(pager_process.in, "w");
+	fputs(s, pager_stdin);
+	fflush(pager_stdin);
+
+	close(pager_process.in);
+	finish_command(&pager_process);
+}
diff --git a/pager.h b/pager.h
index b77433026d..dcccfa632b 100644
--- a/pager.h
+++ b/pager.h
@@ -11,6 +11,7 @@ void term_clear_line(void);
 int decimal_width(uintmax_t);
 int check_pager_config(const char *cmd);
 void prepare_pager_args(struct child_process *, const char *pager);
+void fputs_to_pager(const char* s);
 
 extern int pager_use_color;